[mythtv-users] audio/video studder (WriteAudio: buffer underrun) only with live tv

[Tim Berger]

For various reasons, I'm using mythtv cvs (2005-01-22).  With the
sable releases I was experiencing a loud chirp noise when skipping
around.  Thankfully that's mostly gone now.  So I'm happier using cvs.

With live tv, every few seconds the frontend process outputs:
WriteAudio: buffer underrun

If I pause it for a few seconds, the problem goes away completely. 
The cvs version lets you increase the ringbuffer size, but this seems
to have no effect.  It doesn't seem to matter if /dev/dsp or ALSA is
used for output.  Another interesting point is that the problem rarely
happens immediately after switching to live tv.  It mostly occurs
after the first channel change.  After the first channel change, the
problem does not go away unless the video is paused.

In /lib/modules/2.6.10-1.741_FC3smp/updates/drivers/media/video I've
copied msp3400-ivtv.ko to msp3400.ko.  I undersand that the ivtv
version of this file should be used.

I've tried various version of alsa and ivtv, but they do not seem to
have any effect on this problem.

How odd.  Can anyone shed some light on this?  Thanks!

System information follows:

2.6.10-1.741_FC3smp
alsa-kmdl-2.6.10-1.741_FC3smp-1.0.8-35.rhfc3.at
ivtv-0.3.2b-65.rhfc3.at

2 PVR250's:
Jan 16 18:16:36 mythtv kernel: tveeprom: Hauppauge: model = 32032, rev
= B110, serial# = *******
Jan 16 18:16:36 mythtv kernel: tveeprom: tuner = Philips FI1236 MK2
(idx = 10, type = 2)
Jan 16 18:16:36 mythtv kernel: tveeprom: tuner fmt = NTSC(M) (eeprom =
0x08, v4l2 = 0x00001000)
Jan 16 18:16:36 mythtv kernel: tveeprom: audio_processor = MSP3440 (type = 11)

Jan 16 18:16:38 mythtv kernel: tveeprom: Hauppauge: model = 32552, rev
= C168, serial# =   *******
Jan 16 18:16:38 mythtv kernel: tveeprom: tuner = LG TAPE H001F MK3
(idx = 68, type = 47)
Jan 16 18:16:38 mythtv kernel: tveeprom: tuner fmt = NTSC(M) (eeprom =
0x08, v4l2 = 0x00001000)
Jan 16 18:16:38 mythtv kernel: tveeprom: audio_processor = MSP3440 (type = 11)

-- 
-Tim